Control and data signaling in sc-fdma communication systems

ABSTRACT

An apparatus and method are provided for transmitting control information and data in a DFT based communication system. The method includes placing a reference signal onto a first symbol among a plurality of symbols in one slot; placing a HARQ-ACK onto a second symbol first placed after the first symbol in the one slot; placing the data onto other symbols except for the first symbol; and transmitting a signal including the reference signal, the HARQ-ACK and the data. A part of CQI information is further placed onto at least one symbol, except for the first symbol, in case that the CQI information is present for transmission in the one slot.

PRIORITY

This application is a Continuation Application of U.S. patentapplication Ser. No. 16/906,668, which was filed in the U.S. Patent andTrademark Office (USPTO) on Jun. 19, 2020, which is a ContinuationApplication of U.S. patent application Ser. No. 16/027,859, which wasfiled in the USPTO on Jul. 5, 2018, and issued as U.S. Pat. No.10,700,840 on Jun. 30, 2020, which is a Continuation Application of U.S.patent application Ser. No. 14/863,024, which was filed in the USPTO onSep. 23, 2015, and issued as U.S. Pat. No. 10,038,539 on Jul. 31, 2018,which is a Continuation Application of U.S. patent application Ser. No.14/313,394, which was filed in the USPTO on Jun. 24, 2014, and issued asU.S. Pat. No. 9,300,454 on Mar. 29, 2016, which is a ContinuationApplication of U.S. patent application Ser. No. 13/674,626, which wasfiled in the USPTO on Nov. 12, 2012, and issued as U.S. Pat. No.8,761,130 on Jun. 24, 2014, which is a Continuation Application of U.S.patent application Ser. No. 12/133,120, which was filed in the USPTO onJun. 4, 2008, and issued as U.S. Pat. No. 8,331,328 on Dec. 11, 2012,and claims priority under 35 U.S.C. § 119(e) to U.S. Provisional PatentApplication Ser. No. 60/942,843, which was filed in the USPTO on Jun. 8,2007, the entire content of each of which is incorporated herein byreference.

BACKGROUND 1. Field of the Invention

The present invention is directed, in general, to wireless communicationsystems and, more specifically, to multiplexing control and datainformation in single-carrier frequency division multiple access(SC-FDMA) communication systems.

2. Description of the Related Art

In particular, the present invention considers the transmission ofpositive or negative acknowledgement bits (ACK or NAK, respectively) andchannel quality indicator (CQI) bits together with data information bitsin an SC-FDMA communications system and is further considered in thedevelopment of the 3^(rd) Generation Partnership Project (3GPP) EvolvedUniversal Terrestrial Radio Access (E-UTRA) long term evolution (LTE).The invention assumes the uplink (UL) communication corresponding to thesignal transmission from mobile user equipments (UEs) to a serving basestation (Node B). A UE, also commonly referred to as a terminal or amobile station, may be fixed or mobile and may be a wireless device, acellular phone, a personal computer device, a wireless modem card, etc.A Node B is generally a fixed station and may also be called a basetransceiver system (BTS), an access point, or some other terminology.The ACK/NAK bits and CQI bits may also be referred to simply as controlinformation bits.

The ACK or NAK bits are in response to the correct or incorrect,respectively, data packet reception in the downlink (DL) of thecommunication system, which corresponds to signal transmission from theserving Node B to a UE. The CQI transmitted from a reference UE isintended to inform the serving Node B of the channel conditions the UEexperiences for signal reception, enabling the Node B to performchannel-dependent scheduling of DL data packets. Either or both of theACK/NAK and CQI may be transmitted by a UE in the same transmission timeinterval (TTI) with data or in a separate TTI with no data. Thedisclosed invention considers the former case, which may also bereferred to as data-associated transmission of the ACK/NAK and/or CQI.

The UEs are assumed to transmit control and data bits over acorresponding to a sub-frame. FIG. 1 illustrates a block diagram of thesub-frame structure 110 assumed in the exemplary embodiment of thedisclosed invention. The sub-frame includes two slots. Each slot 120further includes seven symbols and each symbol 130 further includes of acyclic prefix (CP) for mitigating interference due to channelpropagation effects, as it is known in the art. The signal transmissionin the two slots may be in the same part or it may be at two differentparts of the operating bandwidth. Furthermore, the middle symbol in eachslot carries the transmission of reference signals (RS) 140, also knownas pilot signals, which are used for several purposes including forproviding channel estimation for coherent demodulation of the receivedsignal.

The transmission bandwidth (BW) is assumed to include frequency resourceunits, which will be referred to herein as resource blocks (RBs). Anexemplary embodiment assumes that each RB includes 12 sub-carriers andUEs are allocated a multiple N of consecutive RBs 150. Nevertheless, theabove values are only illustrative and not restrictive to the invention.

An exemplary block diagram of the transmitter functions for SC-FDMAsignaling is illustrated in FIG. 2 . Coded CQI bits 205 and coded databits 210 are multiplexed 220. If ACK/NAK bits also need to bemultiplexed, the exemplary embodiment assumes that data bits arepunctured to accommodate ACK/NAK bits 230. Alternatively, CQI bits (ifany) may be punctured or different rate matching, as it is known in theart, may apply to data bits or CQI bits to accommodate ACK/NAK bits. Thediscrete Fourier transform (DFT) of the combined data bits and controlbits is then obtained 240, the sub-carriers 250 corresponding to theassigned transmission bandwidth are selected 255, the inverse fastFourier transform (IFFY) is performed 260 and finally the cyclic prefix(CP) 270 and filtering 280 are applied to the transmitted signal 290.

Alternatively, as illustrated in FIG. 3 , in order to transmit thecontrol (ACK/NAK and/or CQI) bits 310, puncturing of coded data bits 320may apply 330 (instead of also applying rate matching as in FIG. 2 ) andcertain coded data bits (for example, the parity bits in case of turbocoding) may be replaced by control bits. The discrete Fourier transform(DFT) 340 of the combined bits is then obtained, the sub-carriers 350corresponding to the assigned transmission bandwidth are selected 355(localized mapping is assumed but distributed mapping may also be used),the inverse fast Fourier transform (IFFT) 360 is performed and finallythe cyclic prefix (CP) 370 and filtering 380 are applied to thetransmitted signal 390.

This time division multiplexing (TDM) illustrated in FIG. 2 and FIG. 3between control (ACK/NAK and/or CQI) bits and data bits prior to the DFTis necessary to preserve the single carrier property of thetransmission. Zero padding, as it is known in the art, is assumed to beinserted by a reference LE in sub-carriers used by another UE and inguard sub-carriers (not shown). Moreover, for brevity, additionaltransmitter circuitry such as digital-to-analog converter, analogfilters, amplifiers, and transmitter antennas are not illustrated inFIG. 2 and FIG. 3 . Similarly, the encoding process for the data bitsand the CQI bits, as well as the modulation process for all transmittedbits, are well known in the art and are omitted for brevity.

At the receiver, the inverse (complementary) transmitter operations areperformed. This is conceptually illustrated in FIG. 4 where the reverseoperations of those illustrated in FIG. 2 are performed. As it is knownin the art (not shown for brevity), an antenna receives theradio-frequency (RF) analog signal and after further processing units(such as filters, amplifiers, frequency down-converters, andanalog-to-digital converters) the digital received signal 410 passesthrough a time windowing unit 420 and the CP is removed 430.Subsequently, the receiver unit applies an FET 440, selects 445 thesub-carriers 450 used by the transmitter, applies an inverse DFT (IDFT)460, extracts the ACK/NAK bits and places respective erasures for thedata bits 470, and de-multiplexes 480 the data bits 490 and CQI bits495. As for the transmitter, well known in the art receiverfunctionalities such as channel estimation, demodulation, and decodingare not shown for brevity and they are not material to the presentinvention.

The control bits typically require better reception reliability than thedata bits. This is primarily because hybrid-automatic-repeat-request(HAW)) usually applies to data transmission but not to controltransmission. Additionally, ACK/NAK bits typically require betterreception reliability that CQI bits as erroneous reception of ACK/NAKbits has more detrimental consequences to the overall quality andefficiency of communication than does erroneous reception for the CQIbits.

The size of resources in a transmission sub-frame required for controlsignaling for a given desired reception reliability depend on thechannel conditions the signal transmission from a UE experiences and inparticular, on the signal-to-interference and noise ratio (SINK) of thereceived signal at the serving Node B.

There is a need to determine the placement of control bits whentransmitted in the same sub-frame with data bits so that betterreception reliability is provided for the control bits than for the databits.

There is another need to determine the placement of acknowledgement bitsrelative to channel quality indication bits, in case they aresimultaneously multiplexed, in order to provide better receptionreliability for the former.

There is another need to dimension the resources required for thetransmission of acknowledgement bits, in a sub-frame also containingdata bits, as a function of the channel conditions experienced by thesignal transmission from a UE.

SUMMARY

Accordingly, the present invention has been designed to solve theabove-mentioned problems occurring in the prior art, and embodiments ofthe invention provide an apparatus and a method for allocating resourcesin a sub-frame for the transmission of control bits and data bits.

In accordance with an aspect of the present invention, a method isprovided for transmitting control information and data by a userequipment in a DFT based communication system. The method includesplacing a reference signal onto a first symbol among a plurality ofsymbols in one slot; placing a HARQ-ACK onto a second symbol firstplaced after the first symbol in the one slot; placing the data ontoother symbols except for the first symbol; and transmitting a signalincluding the reference signal, the HARQ-ACK and the data. A part of CQIinformation is further placed onto at least one symbol, except for thefirst symbol, in case that the CQI information is present fortransmission in the one slot.

In accordance with an aspect of the present invention, a user equipmentis provided for transmitting control information and data in a DFT basedcommunication system. The user equipment includes a transmitterconfigured to place a reference signal onto a first symbol among aplurality of symbols in one slot, place a HARQ-ACK onto a second symbolfirst placed after the first symbol in the one slot, and transmit asignal including the reference signal, the HARQ-ACK and the data. A partof channel quality indicator (CQI) information is further placed onto atleast one symbol, except for the first symbol, in case that the CQIinformation is present for transmission in the one slot.

In accordance with another aspect of the present invention, a method forreceiving control information and data by a base station in a DFT basedcommunication system. The method includes receiving a signal including areference signal, a HARQ-ACK and the data, the reference signal beingplaced onto a first symbol among a plurality of symbols in one slot;obtaining, from the received signal, the reference signal onto a firstsymbol among a plurality of symbols in one slot; obtaining, from thereceived signal, the HARQ-ACK onto a second symbol first placed afterthe first symbol in the one slot; and obtaining, from the receivedsignal, the data onto other symbols except for the first symbol. A pailof CQI information is further obtained onto at least one symbol, exceptfor the first symbol, in case that the CQI information is present forreception in the one slot.

In accordance with another aspect of the present invention, a basestation is provided for receiving control information and data in a INTbased communication system. The base station includes a receiverconfigured to receive a signal including a reference signal, a HARQ-ACKand the data, the reference signal being placed onto a first symbolamong a plurality of symbols in one slot, obtain, from the receivedsignal, the reference signal onto a first symbol among a plurality ofsymbols in the one slot, obtain, from the received signal, the HARQ-ACKonto a second symbol first placed after the first symbol in the oneslot, and obtain, from the received signal, the data onto other symbolsexcept for the first symbol. A part of CQI information is furtherobtained onto at least one symbol, except for the first symbol, in casethat the CQI information is present for reception in the one slot.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of the presentinvention will be more apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating an exemplary sub-frame structurefor the SC-FDMA communication system;

FIG. 2 is a block diagram illustrative of a first exemplary SC-FDMAtransmitter for multiplexing data bits, CQI bits, and ACK/NAK bits in atransmission sub-frame;

FIG. 3 is another block diagram illustrative of a second exemplarySC-TDMA transmitter or multiplexing data bits, CQI bits; and ACK/NAKbits in a transmission sub-frame;

FIG. 4 is a block diagram illustrative of an exemplary SC-FDMA receiver,corresponding to the first exemplary SC-FDMA transmitter, forde-multiplexing data bits, CQI bits, and ACK/NAK bits in a receptionsub-frame;

FIG. 5 presents un-coded bit error rate (BER) results as a function ofthe symbol number (symbol position) in the sub-frame slot and the LEvelocity;

FIG. 6 is a block diagram illustrating a first method for the selectionof the sub-frame symbols carrying the transmission of CQI bits andACK/NAK bits;

FIG. 7 is a block diagram illustrating a first method for the selectionof the sub-frame symbols carrying the transmission of ACK/NAK bits;

FIG. 8 is a block diagram illustrating a first method for the selectionof the sub-frame symbols carrying the transmission of CQI bits;

FIG. 9 is a block diagram illustrating a second method for the selectionof the sub-frame symbols carrying the transmission of ACK/NAK bits withreduced overhead; and

FIG. 10 is a block diagram illustrating a second method for theselection of the sub-frame symbols carrying the transmission CQI bitsand ACK/NAK bits.

DETAILED DESCRIPTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings. This invention may, however, beembodied in many different forms and should not be construed as limitedto the embodiments set forth herein. Rather, these embodiments areprovided so that this disclosure will be thorough and complete, and willfully, convey the scope of the invention to those skilled in the art.

Additionally, although the invention assumes a single-carrier frequencydivision multiple access (SC-FDMA) communication system, it also appliesto all FDM systems in general and to OFDMA, OFDM, FDMA, DFT-spread OFDM,DFT-spread OFDMA, single-carrier OFDMA (SC-OFDMA), and single-carrierOFDM in particular.

Basically, the system and methods of the embodiments of the presentinvention solve problems related to the need for providing the desiredreliability for the reception of control signaling under indicativetransmission sub-frame structures and provide additional advantages suchas the reduction of resource overhead for the transmission of controlsignals.

A first observation for the sub-frame structure illustrated in FIG. 1 isthat the reference signal (RS) exists only in the middle symbol of eachslot. In case of a mobile terminal, or user equipment (UE), with highspeed, this can substantially degraded channel estimation for symbolslocated further away from the RS (that is, for symbols near thebeginning and end of each slot) due to the faster variation of thechannel medium as the LTE velocity increases. This may be acceptable fordata transmission that is coded, which has typically a relatively largetarget block error rate (BLER), such as 10% or above, and can benefitfrom retransmissions though a conventional HARQ process. Conversely, theCQI and particularly the ACK/NAK have much stricter performancerequirements, HARQ typically does not apply to the correspondingtransmissions, and providing an accurate channel estimate is essentialin achieving the desired reception reliability.

A brief set of simulation results for the un-coded (raw) bit error rate(BER) is provided to illustrate the impact of inaccurate channelestimation on the reception quality as a function of the symbol positionin the slot and the U speed. Table 1 provides the simulation setup underoptimistic conditions for the performance loss due to imperfect channelestimation at symbols further away from the RS for the followingreasons:

Transmission bandwidth is 1 RB. This maximizes power per sub-carrier.

Channel frequency selectivity is large and there are 2 uncorrelated NodeB receiver antennas. This maximizes the slope of the un-coded (raw) BERcurve and minimizes the relative performance loss due to imperfectchannel estimation for a target BER value.

Operating signal-to-interference and noise ratio (SINR) is large. Thisminimizes the impact of inaccurate channel estimation.

TABLE 1 Simulation Assumptions Parameters Assumptions OperatingBandwidth @ 5 MHz @ 2.6 GHz Carrier Frequency Modulation SchemeQuadrature Phase Shift Keying (QPSK) Data Transmission 1 RB Bandwidth(BW) UE Speed 3, 30, 120 and 350 Kilometers per hour (Kmph) TransmissionType Localized (at same RB) over the sub-frame at 3,30 Kmph FrequencyHopping Between Slots at 120 and 350 Kmph Channel ModelGSM—Terrestrial-Urban with 6 paths (TU6) Number of Node B 2 ReceiverAntennas Number of UE 1 Transmitter Antennas

FIG. 5 presents the un-coded BER. At symbol locations symmetric to theRS, the BER is typically the same. At 120 Kmph and 350 Kmph, thetransmission in the first slot is assumed to occur at a different BWthan the one in the second slot (frequency hopped transmission perslot). As only 1 RS per slot is available for channel estimation, theBER is the same at symbols symmetric (equidistant) to the RS. At lowspeeds, such as 3 Kmph, this is also the case because the channel doesnot change over the sub-frame duration. Some small variability doesexist for medium UE speeds, such as 30 Kmph, but, for simplicity, theaverage BER of symbols equidistant to the RS is only shown.

Even under the previous optimistic assumptions for the un-coded (raw)BER degradation due to degraded channel estimation at symbols furtheraway from the RS, at 350 Kmph the BER saturates at the 1^(st)/7^(th) and2^(nd)/6^(th) symbols. However, the impact on the BER of the3^(rd)/5^(th) symbols is rather contained and saturation is avoided (thedifference relative to the BER at 3 Kmph is also partly due to the factthat the latter uses both RS in the sub-frame for channel estimationwhich therefore effectively operates with twice as much SINR). The BERat 120 Kmph is also degraded by about 3 dB for the 1^(st)/7^(th) symbolsand by about 1.5 dB for the 2^(nd)/6^(th) symbols relative to the one ofthe 3^(rd)/5^(th) symbols at about the 1% point. Obviously, due to theflattening of the BER curves for the 1^(st)/7^(th) and 2^(nd)/6^(th)symbols, the degradation will be much larger for BER operating pointsbelow 1% as it is typically needed for the NAK reception.

Based on the results in FIG. 5 it becomes apparent that the controltransmission should be placed with priority immediately next to the RS.

FIG. 6 illustrates such a placement when a UE transmits both ACK/NAKbits 610 and CQI bits 620 during a sub-frame. These control bits areplaced on symbols next to the RS 630 while the data bits 640 areincluded in symbols transmitted over the entire sub-frame (with theobvious exception of the symbols carrying the RS transmission). Due tothe requirement for better reception reliability; the ACK/NAK bits areplaced closer to the RS than the CQI bits.

FIG. 7 illustrates the case in which the UE transmits only ACK/NAK bits710 together with data bits 720 during a sub-frame. The ACK/NAK bits areplaced at the two symbols next to the RS 730 in each of the twosub-frame slots while the data bits are included in symbols transmittedover the entire sub-frame.

FIG. 8 illustrates the case in which the UE transmits only CQI bits 810together with data bits 820 during a sub-frame. The CQI bits are placedat the two symbols next to the RS 830 in each of the two sub-frame slotswhile the data bits are included in symbols transmitted over the entiresub-frame.

To minimize channel estimation losses, the ACK/NAK bits should be placedwith priority in the symbol after the first symbol carrying the RS. Thisdoes not impact demodulation latency as a channel estimate is availableonly after this first RS symbol. To address low SINR or coverage issues,the ACK/NAK bits can also be placed in the symbol before the second RS.For medium UE speeds, this second placement of ACK/NAK bits benefitsfrom improved channel estimation and time diversity while for high UEspeeds, it benefits from frequency and time diversity. This isillustrated in FIG. 9 where the ACK/NAK bits 910 are placed in only onesymbol next to the RS 920 in each slot, these two symbols (one in eachslot) are located between the two RS, while the data bits 930 aretransmitted throughout the sub-frame (with the obvious exception of thesymbols carrying the RS).

Provisioning for the transmission of ACK/NAK bits in the sub-carriersover 2 symbols is typically adequate to achieve the desired BER for theACK reception. Nevertheless, because the NAK reception has typically alower BER target, it is appropriate to have the ACK/NAK transmissionover the number of sub-carriers in 1 symbol in each slot. If furtherACK/NAK transmissions are needed, because of low SINR or coverageissues, the other symbols next, to the RS in the 2 slots may also beused as illustrated in FIG. 6 and FIG. 7 .

Depending on the number of information bits carried in the CQIreporting, which are typically several times more than the ACK/NAKinformation bits, the symbols immediately adjacent to the RS may notsuffice for the CQI transmission, especially for coverage or SINRlimited UEs that are also typically assigned small bandwidth allocations(a small number of RBs). In such cases, the CQI transmission may alsoextend to one or more symbols that are adjacent to the symbols alsocarrying CQI information that are adjacent to the symbols carrying theRS. An exemplary embodiment of this principle is illustrated in FIG. 10. As previously discussed, the location of the ACK/NAK bits 1010 remainsin symbols next to the RS 1030 but the CQI bits 1020 are located insymbols throughout the transmission sub-frame, similarly to the datasymbols 1040.

While the present invention has been shown and described with referenceto certain exemplary embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

What is claimed is:
 1. A method for transmitting control information anddata by a user equipment in a discrete Fourier transform (MT) basedcommunication system, the method comprising: placing a reference signalonto a first symbol among a plurality of symbols in one slot; placing ahybrid automatic repeat request-acknowledgement (HARQ-ACK) onto a secondsymbol first placed after the first symbol in the one slot; placing thedata onto other symbols except for the first symbol; and transmitting asignal including the reference signal, the HARQ-ACK and the data,wherein a part of channel quality indicator (CQI) information is furtherplaced onto at least one symbol, except for the first symbol, in casethat the CQI information is present for transmission in the one slot. 2.The method of claim 1, wherein the reference signal is a demodulationreference signal.
 3. The method of claim 1, wherein the HARQ-ACK and thepart of the CQI information are placed onto corresponding sub-carriersbased on localized sub-carrier mapping in a frequency domain.
 4. Themethod of claim 1, wherein one or more symbols, except the first andsecond symbols, are additionally used to place the HARQ-ACK in case thatfurther transmission of the HARQ-ACK is needed.
 5. A user equipment fortransmitting control information and data in a discrete Fouriertransform (DFT) based communication system, the user equipmentcomprising: a transmitter configured to: place a reference signal onto afirst symbol among a plurality of symbols in one slot, place a hybridautomatic repeat request-acknowledgement (HARQ-ACK) onto a second symbolfirst placed after the first symbol in the one slot, and transmit asignal including the reference signal, the HARQ-ACK and the data,wherein a part of channel quality indicator (CQI) information is furtherplaced onto at least one symbol, except for the first symbol, in casethat the CQI information is present for transmission in the one slot. 6.The user equipment of claim 5, wherein the reference signal is ademodulation reference signal.
 7. The user equipment of claim 5, whereinthe HARQ-ACK and the part of the CQI information are placed ontocorresponding sub-carriers based on localized sub-carrier mapping in afrequency domain.
 8. The user equipment of claim 5, wherein one or moresymbols, except the first and second symbols, are additionally used toplace the acknowledgement information in case that further transmissionof the acknowledgement information is needed.
 9. A method for receivingcontrol information and data by a base station in a discrete Fouriertransform (DFT) based communication system, the method comprising:receiving a signal including a reference signal, a hybrid automaticrepeat request-acknowledgement (HARQ-ACK) and the data, the referencesignal being placed onto a first symbol among a plurality of symbols inone slot; obtaining, from the received signal, the reference signal ontoa first symbol among a plurality of symbols in one slot; obtaining, fromthe received signal, the HARQ-ACK onto a second symbol first placedafter the first symbol in the one slot; and obtaining, from the receivedsignal, the data onto other symbols except for the first symbol, whereina part of channel quality indicator (CQI) information is furtherobtained onto at least one symbol, except for the first symbol, in casethat the CQI information is present for reception in the one slot. 10.The method of claim 9, wherein the reference signal is a demodulationreference signal.
 11. The method of claim 9, wherein the HARQ-ACK andthe part of the CQI information are obtained onto correspondingsub-carriers based on localized sub-carrier mapping in a frequencydomain.
 12. The method of claim 9, wherein one or more symbols, exceptthe first and second symbols, are additionally used to obtain theHARQ-ACK in case that further transmission of the HARQ-ACK is needed.13. A base station for receiving control information and data in adiscrete Fourier transform (DFT) based communication system, the basestation comprising: a receiver configured to: receive a signal includinga reference signal, a hybrid automatic repeat request-acknowledgement(HARQ-ACK) and the data, the reference signal being placed onto a firstsymbol among a plurality of symbols in one slot, obtain, from thereceived signal, the reference signal onto a first symbol among aplurality of symbols in the one slot, obtain, from the received signal,the HARQ-ACK onto a second symbol first placed after the first symbol inthe one slot, and obtain, from the received signal, the data onto othersymbols except for the first symbol, wherein a part of channel qualityindicator (CQI) information is further obtained onto at least onesymbol, except for the first symbol, in case that the CQI information ispresent for reception in the one slot.
 14. The base station of claim 13,wherein the reference signal is a demodulation reference signal.
 15. Thebase station of claim 13, wherein the HARQ-ACK and the part of the ONinformation are obtained onto corresponding sub-carriers based onlocalized sub-carrier mapping in a frequency domain.
 16. The basestation of claim 13, wherein one or more symbols, except the first andsecond symbols, are additionally used to obtain the HARQ-ACK in casethat further reception of the HARQ-ACK is needed.